Questions tagged [vision]

For questions regarding the visual system, which serves to transduce light energy into neural impulses, or regarding visual perception, how we interpret such incoming visual information.

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What are biologically plausible ways to model binocular disparity?

I figure there is a vast body of literature on stereovision, both neurophysiological and computational studies. Computer Vision also provides some algorithmic insight on implementing binocular ...
compephys's user avatar
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Number of presynaptic inputs per cell in primary visual cortex

I have been digging in the literature lately, but I haven't found a nice answer with clear cut numbers (avg +- std) to this question: How many presynaptic inputs receives a pyramidal cell in primary ...
SmCaterpillar's user avatar
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1 answer
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Is there a hierarchy of gestalt visual stimuli processing?

Let's say that we have a set of shapes. They can be grouped according to the different Gestalt laws of grouping. However, different Gestalt principles will divide the set into different groups, e.g. ...
Vitaly Mijiritsky's user avatar
8 votes
2 answers
260 views

Are there physical techniques to relieve eye strain? [closed]

I asked a question about eye strain Does looking into a mirror relieve eye strain in a similar way to looking at distant objects?. Are there any physical exercises or techniques that can help to ...
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8 votes
1 answer
142 views

Are there any models of the human visual field of view taking into account head, neck and eye movements and calculating likelihood of fixation?

I would like to know if there are studies that (1) model the field of view taking into account all degrees of freedom of the head, neck and eyes and (2) if there is any probabilistic model assigned to ...
Angeliki's user avatar
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7 votes
1 answer
278 views

How do people that can't perceive 3D view a stereoscopic 3D image or movie?

According to Mendiburu (2009), 3-15% of the people can't view a stereoscopic 3D image or movie, mostly due to poor binocular vision. Imagine one of those is in the movie theater, trying to watch a 3D ...
Mien's user avatar
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How does the brain break down visual information for processing? What "channels" is visual input broken into?

Some time ago I remember reading about how the human brain breaks down visual information into a number of individual "channels". For example, one channel might focus on edges and lines, another ...
David Parks's user avatar
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1 answer
2k views

Do we recognize ourselves better when we see our mirror image?

A friend of mine recently noticed that we both have a birthmark on the face. He looked at me and said that we have exactly the same mark. But he has it left and I right. But, when looking in a mirror, ...
draks ...'s user avatar
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7 votes
2 answers
159 views

How fast is the visual system?

I've heard that the visual system is one of our slowest sensory systems. How fast is the visual system, and how does it compare to other sensory systems (auditory, mechanosensory, pain, etc.)? For ...
Victor L's user avatar
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1 answer
227 views

How is light processed by the human brain when awake and in dreams?

I've recently seen this great video: How your brain tells you where you are. The video discusses how certain cells within the brain fire based on proximity to objects. There are great examples of ...
Alex Stone's user avatar
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How is the biological error signal in predictive coding computed?

I am quite inspired by the results obtained by PredNet, which implements a predictive coding model using artificial neural networks. They compute the prediction error as a simple subtraction, and then ...
Toke Faurby's user avatar
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How are humans able to read scrambled text/characters (e.g., CAPTCHA)?

So I'm doing a research on developing a new text-based CAPTCHA system. I've devised a scheme where characters in a text are broken/split individually and randomly, making it difficult for OCR machines ...
Sarthak Singhal's user avatar
7 votes
1 answer
112 views

Relationship between oculometry/pupillometry and disorders of consciousness

I recently got to wondering whether certain eye movements or pupillary responses were correlated with disorders of consciousness (coma, VS, MCS, or even locked-in syndrome). I know that the pupillary ...
Louis Thibault's user avatar
7 votes
1 answer
225 views

How come we see a line when there isn't one in this picture?

I got this picture I generated myself and I don't understand how come we can see two diagonal lines when, I think, there is no actual lines. Zooming in: Center: Just another 2px wide square… After ...
jeromej's user avatar
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1 answer
248 views

Do eyes accommodate to color?

I've heard that our eyes accommodate between colors too far from each other in the visible spectrum. I imagine it's not a true focal point accommodation, but rather linked with how brain processes the ...
dwelle's user avatar
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1 answer
110 views

Find the panda among snowmen!

I just saw this picture puzzle, and found it easily by doing a row-by-row scan, but it seems harder to find it just by looking around. I was thinking that the puzzle was intentionally designed to draw ...
user21820's user avatar
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0 answers
660 views

Has there been a neuroscientific explanation of the color phi phenomenon?

The color phi phenomenon is a perceptual illusion in the visual domain which was demonstrated in an experiment by Kolers and von Grunau (1976). The experiment is as follows. A sequence of coloured (...
Lazaros Mitskopoulos's user avatar
6 votes
2 answers
693 views

Are closed eye movements related to the content of dreams or the imagination?

During rem sleep there are observed eye movements, which seem like they would correlate with the person visualizing their dreams. Do their eye movements actually try to follow what they're dreaming ...
user avatar
6 votes
1 answer
206 views

If I think of a checkerboard, is there a similar structure to see in my visual cortex?

When I´m imagining a checkerboard in my mind, can one find, with all kinds of fancy equipment, a corresponding figure in the area of my visual cortex? For example, the neurons firing in such a way as ...
Deschele Schilder's user avatar
6 votes
2 answers
5k views

Sensitivity of human eye to luminance

I heard once that the human eye has a logarithmic scale for luminance, e.g. to "feel" that a surface is three times as luminous compared to another, the former emits a light 8 times more powerful than ...
Lorenzo Pistone's user avatar
6 votes
2 answers
2k views

Is there a difference between visual short term memory and visual working memory?

As far as I can tell the two terms are used interchangeably. Do these two separate terms exist for historical reasons, or is there a distinction I'm missing?
Louis Thibault's user avatar
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2 answers
454 views

Do the colour blind have a distinct visual cortex structure?

Studying the structure of the visual cortex, it seems there are many neural structures specifically dedicated to detecting and interpreting colour. For example, parvocellular cells are particularly ...
Seanny123's user avatar
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Why is the occipital lobe behind instead of in front?

These are regions of our brain: Our eyes are in front below our forehead, however, the visual area Occipital Lobe is behind. Are there any biological reasons for this? why shouldn't Occipital Lobe be ...
Dan D.'s user avatar
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6 votes
1 answer
362 views

Visual acuity and offset stimuli

I'm currently setting up and experiment that utilises a visual search task that contains a circular array of target letters and a distractor that falls outside the circle. Obviously the further away ...
Rooirokbokkie's user avatar
6 votes
1 answer
101 views

Any research on how we use visual category information in visuomotor tasks?

So I've been reading up on the Two-streams Hypothesis*, and it bothers me that the explanations both sides give only extend to tasks involving one type of visual information. For example, an ...
zergylord's user avatar
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1 answer
318 views

Is V1 involved in visual imagery?

It's well known that mental imagery shares the neural substrates of its respective modality, despite dissociable multivariate patterns. For example, visual imagery can be decoded across the ventral ...
mrt's user avatar
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6 votes
1 answer
564 views

In psychophysics, why are log luminance rather than absolute luminance values reported?

Are there any papers which justify converting into log luminance? For example papers showing humans being sensitive to changes in log luminance rather than luminance per se?
Lenna's user avatar
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1 answer
505 views

Why is my Gabor patch not resizing as a function of the bounding box?

I'm trying to create a Gabor patch of variable size for an upcoming experiment. Below is the python function used to generate the code. The code was ported from this tutorial for Matlab (assume <...
Louis Thibault's user avatar
6 votes
1 answer
365 views

How much red/orange is needed to stimulate hunger?

A common claim thrown around is that red and orange are great for restaurants because it stimulates hunger. However, I've heard time and time again that this does not work in web design because you ...
Ben Brocka's user avatar
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6 votes
1 answer
439 views

How long does it take to learn to cane travel?

How long does it take the average person (either sighted or blind) to learn to use the guide cane successfully for mobility purposes? Source: Lions. Because required training times will depend on ...
AliceD's user avatar
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2 answers
69 views

Do we have a predisposition to view visual stimuli in a clockwise pattern?

I understand that we typically view the center of the image first and then are likely to move on a horizontal axis, but is there evidence that we tend to follow a clockwise path when viewing more ...
braintoast's user avatar
6 votes
1 answer
339 views

Does the structure of consciousness mimic that of the visual process?

It seems to me that the structure of the conscious mind has some strong similarities to the way our visual field functions. The visual field has a strong and detailed focus at the center, and this is ...
Clay C's user avatar
  • 61
6 votes
1 answer
1k views

What is the brain power devoted to vision and haptics?

I heard a talk by Vincent Hayward on the sense of touch as a multi-modal system, where he claimed that the brain power devoted to haptics is at least as big as the one devoted to vision. I have found ...
Jakob's user avatar
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6 votes
1 answer
321 views

How is the focal point determined when looking into a clear sky?

When looking into a clear blue sky, no cloud, birds, trees or any object to give a frame of reference. When a person is actively looking, as opposed to day dreaming or gazing. The sky goes for a long ...
user avatar
6 votes
1 answer
2k views

Are scintillating scotomas really caused by cortical spreading depression? If so, how is this known to be true?

I have just read about a visual effect called a scintillating scotoma. Many variations occur, but scintillating scotoma usually begins as a spot of flickering light near or in the center of the ...
uhoh's user avatar
  • 473
6 votes
1 answer
174 views

What are the effects of visual deprivation on mental health and the other senses?

How do blind people who haven't always been visually impaired deal with their day-to-day lives? I've heard rumors (very, very unreliable rumors) that once you stay in the dark for too long you'll ...
Sam Chahine's user avatar
6 votes
1 answer
517 views

Computational model of biological object recognition

The human brain can achieve a remarkable ability to recognize visual patterns in an Invariant, selective and fast manner. The human visual system is quite powerful. It has an exquisite selectivity ...
Christina's user avatar
  • 201
6 votes
1 answer
866 views

Visual field testing: Choose between Yes/No, 2AFC, and 2IFC task?

As a newbie to psychophysics experiment, I have a small project to do visual field testing on healthy, adult, naive subjects. The experiment stimulus is a small sine grating (0.3 degree, 6 cycles/...
Cloudy's user avatar
  • 245
6 votes
0 answers
102 views

Grating orientation & frequency which induces highest gamma

I am doing some research on perception and gamma activity in V1 area. To check some of my results I need to find an experimental result, from which I would know which orientations and frequencies of ...
Ilya Kuzovkin's user avatar
5 votes
3 answers
2k views

How to use a QUEST staircase in 2-AFC?

Firstly, I need to declare that I am not psychologyst, however I am currently working on visual recognition research. To be precise, I working on face recognition deficits in Autism Spectrum Disorder. ...
Enasi's user avatar
  • 173
5 votes
3 answers
182 views

Are there any cognitive models for visual navigation?

I've seen a few neuroscience accounts of visual navigation and many A.I. projects, but no psychologically plausible accounts that actually solve the computational problem (i.e. produce a working model)...
zergylord's user avatar
  • 2,404
5 votes
3 answers
2k views

The interactions between hallucinations and reality in people with schizophrenia

A person with schizophrenia sees a door become open, while in reality it's closed. What would he see when he tries to pass through the door? Bumps into an invisible obstacle. He sees the door become ...
asmani's user avatar
  • 147
5 votes
1 answer
888 views

Distortion of faces presented serially in peripheral vision

I've kind of already answered this question for myself, but I can't resist sharing it anyway. Please feel welcome to add anything you can in another answer. Stare at the cross in the middle and try to ...
Nick Stauner's user avatar
  • 9,414
5 votes
2 answers
2k views

Minimum duration for presenting a visual stimulus on screen

My experiment involves presenting simple visual stimuli briefly on screen (200 ms to 1000 ms). The stimuli would be simple enough (e.g. a circle and a line) but I want to use a range of durations to ...
Wynn's user avatar
  • 53
5 votes
1 answer
389 views

Do cats exhibit the bouba/kiki effect?

I was fascinated when I first read Ramachandran's article about kiki bouba effect, and I was wondering if cats experience the same thing... As Ramachandran proved, our angular gyrus is responsible for ...
Sorosh Samiei's user avatar
5 votes
2 answers
811 views

What is the minimum angle off horizontal before a line visually appears inclined at first glance?

Here is a straight line, which visually looks like a straight line: At first look (lets say minimum 2–3 sec.) the line below looks straight, but after some time you can see that it is actually an ...
vasili111's user avatar
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5 votes
1 answer
1k views

How does the brain read rotated text?

Suppose a human ran across a letter written at a 45 degree angle. How does the brain read this text? Most people don't often see text written at an angle, so it seems safe to assume that the brain ...
Victor L's user avatar
  • 375
5 votes
1 answer
257 views

Are we actually seeing black colored objects?

We know that black objects absorb light with almost all the frequencies of the visible spectrum. This means there will not be any frequency of light reflected and falling on our retina, in order for ...
Vaishakh Rajan K's user avatar
5 votes
1 answer
127 views

When your two eyes disagree sharply

Now and then, the image from each eye is so different from the other that it seems the brain has trouble combining them into a coherent image. You can create this situation by putting a hand or sheet ...
Luke Sawczak's user avatar
5 votes
1 answer
1k views

How does the brain structure 3D visual data?

Adobe Illustrator has taken over five minutes (and counting) to render a vector 2D image rotated 18° in 3D on my computer. And yet, I and nearly anyone else can easily visualize the subject rotated ...
TheEnvironmentalist's user avatar